Integrated Management of Stem Rot Disease (Sclerotium rolfsii) in Groundnut Under Rice-Based Cropping Systems

Stem rot of groundnut caused by Sclerotium rolfsii Sacc. is a major constraint to productivity under rice-based cropping systems. The pathogen was isolated from diseased groundnut stems and evaluated against seven fungicides at 50, 100, 150, 250 and 500 ppm and six bio-control agents under in vitro conditions. Among the fungicides, trifloxystrobin + tebuconazole (50 ppm), tebuconazole (250 ppm), azoxystrobin (150 ppm) and azoxystrobin + difenoconazole (100 ppm) were most effective, inhibiting mycelial growth of S. rolfsii by up to 89.69%. Among the bio-control agents, Trichoderma harzianum showed the highest antagonistic activity, suppressing mycelial growth by 60.97% three days after inoculation. Based on in vitro efficacy, a field experiment was conducted during the summer seasons of 2018–2020 under a rice-based cropping system. The results revealed that the integrated treatment comprising seed treatment with azoxystrobin 23 SC @ 1 ml kg^-1 along with soil application of T. harzianum 1.5% WP @ 2.5 kg ha^-1 at sowing recorded the lowest plant mortality (15.24%). This treatment also significantly reduced pod rot (1.79 pods plant^-1) and improved plant height (50.37 cm), number of pods per plant (12.93), pod yield (1983 kg ha^-1) and haulm yield (5845 kg ha^-1). The study demonstrates that integrated use of fungicide and bio-control agent is an effective and sustainable strategy for managing stem rot of groundnut.